Study: Global warming will bring more intense downpours

Global warming could bring more intense rain, according to a new NOAA study.

Jim Rassol, SunSentinel

Jim Rassol, SunSentinel

Ken KayeSun Sentinel

South Florida, no stranger to heavy rains, could see even more torrential downpours, thanks to global warming.

Much of the Northern Hemisphere will be subject to more extreme rain events because of increasing levels of greenhouse gases, according to a study conducted by the National Oceanic and Atmospheric Administration and published in Geophysical Research Letters, a scientific journal.

“We have high confidence that the most extreme rainfalls will become even more intense, as it is virtually certain that the atmosphere will provide more water to fuel these events,” said Kenneth Kunkel, a senior research professor at North Carolina State University and lead author of the paper.

South Florida averages about 60 inches of rain per year, with about 70 percent of that produced during the rainy season, mid-May through mid-October.

The region usually sees flooding rains every summer; for instance, Hurricane Isaac’s outer bands produced about 15 inches of rain in western Palm Beach County in August, leaving severe flooding in some areas.

According to the study, a 20 to 30 percent increase in rainfall during torrential downpours is possible “over large portions of the Northern Hemisphere by the end of the 21st century if greenhouse gases continue to rise at a high emissions rate.”

Kunkel said the overall rainfall a region receives won’t necessarily increase, only rainfall rates during “the heaviest of storms.”

The study was conducted by a team of researchers from the North Carolina State University and NOAA’s National Climatic Data Center in Asheville, N.C., among other agencies.

Researchers used climate models to focus on how increases in greenhouse gas could affect rainfall and winds. Their findings could impact how engineers will design dams, culverts, detention ponds and other water control structures in the future.

Thomas Karl, director of the National Climatic Center and the study’s co-author, said the next challenge is to find ways to avoid potential disasters associated with heavy rains.

“Findings of this study, and others like it, could lead to new information for engineers and developers that will save lives,” he said.